Multidrug resistance proteins

Abstract

A novel protein associated with multidrug resistance in living cells and capable of conferring multidrug resistance on a cell is disclosed. Nucleic acids encoding the novel multidrug resistance protein are also disclosed. Transformant cell lines which express the nucleic acid encoding the novel protein are also disclosed. Antibodies which bind the novel multidrug resistance protein are also disclosed. Diagnostic and treatment methods using the novel proteins, nucleic acids, antibodies and cell lines of the invention are also encompassed by the invention.

We claim: 
     
       1. An isolated protein which is encoded by a nucleic acid molecule which hybridizes under high stringency conditions, with a wash step in about 0.2×SSC at 50° C., to a nucleic acid having the nucleotide sequence shown in SEQ ID NO: 1, wherein the protein confers multidrug resistance, including resistance to at least two drugs selected from the group consisting of anthracyclines, epipodophyllotoxins and Vinca altloids, on a drug sensitive mammalian cell when the protein is expressed in the cell, said multidrug resistance not being substantially reversed by chemosensitizers which reverse P-glycoprotein-mediated multidrug resistance. 
     
     
       2. The protein of claim 1, comprising an amino acid sequence represented by the formula V-W-X-Y-Z in regions V, X and Z, wherein V are amino acid residues corresponding to amino acid residues from about 1 to about 660 of SEQ ID NO: 2, W are amino acid residues of a nucleotide binding fold corresponding to amino acid residues from about 661 to about 810 of SEQ ID NO; 2, X are amino acid residues corresponding to amino acid residues from about 811 to about 1309 of SEQ ID NO: 2, Y are amino acid residues of a nucleotide binding fold corresponding to amino acid residues from about 1310 to about 1469 of SEQ ID NO: 2, and Z are amino acid residues corresponding to amino acid residues from about 1470 to about 1531 of SEQ ID NO: 2, wherein the protein confers multidrug resistance, including resistance to at least two drugs selected from the group consisting of anthracyclines, epipodophyllotoxins and Vinca alkaloids, on a drug sensitive mammalian cell when the protein is expressed in the cell, said multidrug resistance not being substantially reversed by chemosensitizers which reverse P-glycoprotein-mediated multidrug resistance. 
     
     
       3. The protein of claim 2, wherein regions W and Y consist of the amino acid sequences shown for these regions in SEQ ID NO: 2. 
     
     
       4. The protein of claim 2, wherein at least one of (i) a nucleotide sequence of said nucleic acid molecule encoding region V, (ii) a nucleotide sequence of said nucleic acid molecule encoding region X and (iii) a nucleotide sequence of said nucleic acid molecule encoding region Z hybridizes under high stringency conditions, with a wash step in about 0.2×SSC at 50° C., to a corresponding nucleotide sequence of SEQ ID NO: 1. 
     
     
       5. An isolated protein which is encoded by (i) the nucleotide sequence shown in SEQ ID NO: 1, or (ii) an allelic variant of SEQ ID NO: 1, wherein the protein confers multidrug resistance, including resistance to at least two drugs selected from the group consisting of anthracyclines, epipodophyllotoxins and Vinca alkaloids, on a drug sensitive mammalian cell when the protein is expressed in the cell, said multidrug resistance not being substantially reversed by chemosensitizers which reverse P-glycoprotein-mediated multidrug resistance. 
     
     
       6. The protein of claim 3, wherein at least one of (i) a nucleotide sequence of said nucleic acid molecule encoding region V, (ii) a nucleotide sequence of said nucleic acid molecule encoding region X and (iii) a nucleotide sequence of said nucleic acid molecule encoding region Z hybridizes under high stringency conditions, with a wash step in about 0.2×SSC at 50° C., to a corresponding nucleotide sequence of SEQ ID NO: 1. 
     
     
       7. The protein of claim 2, 4, 1, 5 or 6, which is immunogenic. 
     
     
       8. An isolated protein comprising the amino acid sequence shown in SEQ ID NO: 2. 
     
     
       9. The isolated protein of claim 8, which consists of the amino acid sequence shown in SEQ ID NO: 2. 
     
     
       10. An isolated protein comprising the amino acid sequence shown in SEQ ID NO: 4. 
     
     
       11. The isolated protein of claim 10, which consists of the amino acid sequence shown in SEQ ID NO: 4. 
     
     
       12. An isolated protein comprising the amino acid sequence shown in SEQ ID NO: 6. 
     
     
       13. The isolated protein of claim 12, which consists of the amino acid sequence shown in SEQ ID NO: 6. 
     
     
       14. The isolated protein of claim 7, or a portion thereof, comprising amino acid residues 932-943 of the protein shown in SEQ ID NO: 2, wherein the isolated protein or portion thereof is not the protein of SEQ ID NO: 2. 
     
     
       15. The protein portion of claim 14, consisting of from about amino acid residue 932 to about amino add residue 943 of the protein shown in SEQ ID NO: 2. 
     
     
       16. The isolated protein of claim 7, or a portion thereof, comprising amino acid residues 1126-1239 of the protein shown in SEQ ID NO: 2 wherein the isolated protein or portion thereof is not the protein of SEQ ID NO: 2. 
     
     
       17. The protein portion of claim 16, consisting of from about amino acid residue 1126 to about amino acid residue 1239 of the protein shown in SEQ ID NO: 2. 
     
     
       18. The isolated protein of claim 7, or a portion thereof, comprising amino acid residues 1123-1236 of the protein shown in SEQ ID NO: 6, wherein the isolated protein or portion thereof is not the protein of SEQ ID NO: 6. 
     
     
       19. The protein portion of claim 18, consisting of from about amino acid residue 1123 to about amino acid residue 1236 of the protein shown in SEQ ID NO: 6.